Pump having rolling pistons working in nuts



1,625,794 Aprll 26 1927- msTLElN ET AL PUMP HAVING ROLLING PISTONS WORKING IN NUTS Filed Feb. 21. 1924 2 Shets-Sheet 1 ,4 W

1? A 2K 2 L d a 1927. l 625 794 Apnl P. CHRISTLEIN ET AL PUMP HAVING ROLLING PISTONS WORKING IN NUTS Filed Feb. 2 1924 2 Sheets-Sheet 2 Patented Apr. 26,1927.

UNITED STATES 1,625,794 PATENT OFFICE.

PAUL CHRIBTLEIN, OF NUREMBERG, AND KARL WERNER, OI? NUBEMBEBG- EIBACH, GERMANY.

PUMP HAVING ROLLING PISTONS WORKING IN NUTS.

Application filed February 21, 1924, Serial No. 694,227, and in Great Britain October 9, 1923.

This invention relates to pumps having rolling pistons working in nuts of large diameter and in which a trough fills the free space between the nut and the rolling piston. Pumps of this type have an automatic and free suction up to a suction height of approximately 28 feet. If the pump is running at a high number of revolutions, especially with large suction heights or when m lifting thick or viscid fluids, the pump chamber may not be completely and continuously filled owing to a low admission feed and to a small cross section, and consequently interruptions of the stream of liquid may in take place.

Now according to the invention this disadvantage is obviated by providing at the admission side of the pump inlet passages or conduits which are so arranged that the velocity of the fluid to be lifted arriving therein is increased, as the resistance opposing the passage of the fluid through the said conduits is reduced owing to the shape of the conduit, and means may also be provided especially for accelerating the flow in the the said conduits, such as a wing or axial pump rotating with the trough. This dynamic pump imparts to the fluid to be lifted an increased velocity, so that it is forced, with an acceleration corresponding to the peripheral velocity of the rolling piston pump, into the suction chamber of the rollmg piston pump and entirely fills it. The wing or axial pump laced in front can be driven from the sha or from the rolling piston pump on which it may be mounted. In this way .a substantial improvement of the volumetric efliciency of the pump can be obtained and also thick or viscid fluids can be lifted by high speed pumps at a great height of suction.

The conduits, which facilitate or accelerate the admission into the pump of the fluid to be lifted, may be obtained by bevelling or reducing the running out ends of the screw thread in the rolling piston, and furthermore, the part of the nut at the inlet side may also be cut away where no doublewalled guiding of the liquid through the flange or sides of the nut takes place. In this way the resistances are removed which oppose the rapid admission of the fluid to be lifted into the machine, more especially in the case of viscid fluids which tend to diminish the velocity of entrance. At the same time the further advantage is secured of dispensing with the blade-shaped running out ends of the screw thread which are liable to become bent or jammed. If necessary both methods may be used simultaneously, that is, the arrangement in front of a wing or axial pump, and bevelling off the running out ends of the screw thread, in order to form the admission side of the pump in such manner that suction can be accomplished at great heights with a great number of revolutions of the machine, for example in the case of condensate pumps, or when lifting very viscid or thick fluids.

The accompanying drawings show in Figures 1 to 5 respectively two constructional examples of the use of the invention, and Figures 6 to 10 illustrate further developments thereof. Figures 1 to 3 illustrate a pump in which a wing pump is placed at the inlet end of the main pump, and Figures 4 and 5 show the bevelling off of the screw thread between the nut and rolling piston.

In Figure 1 a duplex pump is shown for example, which consists of the nuts M, the trough N and the pair of rolling pistons R rotatably mounted in the trough N which is driven from the outside by means of the shaft B. The fluid to be lifted enters at the pipe E and passes out at the ressure side A. At each admission side in ront of the two halves of the pump a wing or vane wheel F is placed, the said wheel being fastened to the trough N and rotating therewith. The vane wheels F are, as shown in detail in Figures 2 and 3, made with such a type of blade or vane that they hurl the fluid into the suction chamber of the pump at the desired rate. In front of each accelerating wheel can be placed a guide device L which feeds the fluid to the accelerating wheel with the minimum of resistance.

The double or duplex pump shown in Figure 1 may be improved in that the running out ends a and d of'the rolling pistons and of the nuts may be bevelled off at the admission side, so that they terminate in obtuse blades which can be rounded off by hand. An admission canal or conduit is thus obtained which facilitates the entry of the fluid to be lifted and which reduces to a minimum the resistance thereto. Figures-4 and 5 show in detail the nuts and the rolling threads bevelled off.

' in lateral elevation in Figu As shown in cross section in Fi e 6 and tion of the conduit can be -still further developed by dispensing with the triangular part of the nut at the admission side, where there is no double-sided fguiding of the fluid by the flanks or sides 0 the nuts. In Fi ure 6 this part is marked :21. a

Figures 8, 9 and 10 show a further improvement, m which the nut shown in Figures 6 and 7 is also coned out at the admission end to reduce the resistance presented to the enterin fluid. Figures 9 and 10 show respective a cross section and a lateral elevation, W 1st Figure 8 is a development showing the absence of the part to. A recess such as that indicated at m can also be provided at the outlet side of the nut so as to re at the transformation of kinetic energy into pressure. In Figures 6 to 9 this recess in the outlet side is shown at the left side of the nut.

What we claim and desire to secure by Letters Patent of the United States is 1. In a fluid pump, a rolling threaded piston, a nut in which the piston rotates,

and feed conduits provided at-the admission side of the ump, said conduits being constructed to increase the velocity of admission of the fluid to the pump.

2. In a fluid pump, a rolling threaded piston, a nut in which the piston rotates,

feed conduits provided at the admission side of the pump, and-:an accelerating-wheel at the admission side of the pump for increasing the velocity of admission of the fluid to the pump.

'3. In a pump according to claim 2, a guidre 7 t e forma-.

ing device mounted in front of the accelerating wheel for iding the fluid to the wheel. I

4. In a flui pum a rolling threaded piston, a nut in whic the piston rotates, a trough fillingthefree space between the nut and the iston, and an accelerating wheel at the a ission side of the pump for in- I creasing the velocity of admission of the fluid to the pump, said wheel being operatively connected with the trou h. e

5. A pump according to 01mm 1 in which the running out ends of the es of the I screw threads of the nut and of t e rolling piston are beveled 05.

6. In a fluid ump, a rolling threaded piston,.a nut in w ich the piston rotates, and feed conduits provided at the admission side I of the pump, the running out ends of the edges of the screw threads of the nut and of the rolling iston being beveled ofi.

7. In a uid pump, a rolling threaded piston, a nut in which the piston rotates, O and feed conduits provided at the admission side of the pump, that part of the nut at which no double-sided guiding of the fluid takes place by means of the flanks of the screw threads being omitted at the admission side of the pump.

8. In a fluid pump, a rolling threaded piston, a nut in which the iston rotates and I feed conduits provided at t e admission side of the ump, that part of the nut at which no dou le-slded guiding of the fluid takes place by means of the flanks of the screw vthreads being omitted at the outlet side of the pump.

PAUL CHRISTLEIN. KARL WERNER. 

